1. Field of the Invention
The present invention pertains to coin recognition devices, and more particularly, to a system for determining, based on diameter measurements, whether given coins or tokens correspond with well-known denominations. The system also provides for computing the cumulative value of a series of coins taken in payment of, for example, transportation fares or tolls.
2. Background Information
A variety of devices and mechanisms for testing coins, and for orienting, sorting and feeding same, have been known in the art. In order to provide a proper context for an understanding and appreciation of the present invention, reference may be made to the following U.S. patents as background material: U.S. Pat. Nos. 2,903,117, 3,738,469, 3,752,168, 3,788,440, 3,797,307, 4,249,648.
In particular, U.S. Pat. No. 3,797,307 is regarded as being the most pertinent of the references cited above. The invention described therein relates to coin discrimination devices and, more particularly, to a system for determining the denomination of coins and for rejecting undesired coins. The principle or basis for distinguishing among differing coins is by measuring two of their physical characteristics, such as diameter and acceptance ratio, the acceptance ratio being defined as the ratio of the coin's electrical conductivity to its density. The invention therein described relies upon the effect produced on an electrically conductive nonferromagnetic coin passing through a stationary magnetic field; namely, the retardation of the initial velocity of the coin in an amount primarily dependent upon the previously noted acceptance ratio of the coin. Thus, the ultimate velocity attained by such coin, when sensed downstream of that magnetic field by the use of a pair of suitably spaced sensors, becomes a measure of the coin authenticity and denomination.
The system of U.S. Pat. No. 3,797,307 also envisions a specialized means of measuring the diameter of a moving coin by measuring the time required to pass by one of the sensors, providing a velocity-dependent measurement of the chord of the coin at the height of that sensor above an inclined coin-support track. Necessarily, because of this arrangement involving the magnetic field and the inclined track, a coin fed through such system has to be stopped at the top of the track, then released for accelerated movement responsive to the combined effects of gravity, friction and the magnetic field. As a consequence, a considerable period of time is wasted with such procedure; hence, a significant time period is consumed in determining coin diameters measured from the instant at which coins first enter the system.
Whatever the particular merits of the system of U.S. Pat. No. 3,797,307, and whatever the various details of the structural embodiments therein disclosed, the fact remains that said system presents inherent ambiguities in measurement, and is not very tolerant of vibrational or frictional effects; furthermore, it is dependent on the use of a magnetic field to affect the coin velocity, with the paradoxical result that only nonferromagnetic, electrically conductive, coins can be measured. This is because the system relies on eddy currents being induced in electrically conductive material. However, a magnetic coin would be attracted and retained by the magnet utilized for developing the primary field. Hence, a magnetic coin scavenging device would have to be installed upstream of the measurement system.
It is therefore a primary object of the present invention to provide a simplified coin measurement system that will measure or recognize coins, tokens, or other objects, whether they be made of metal, plastic or whatever material, instead, for example, of being limited to only nonferromagnetic, metallic objects.
Another primary object is to avoid ambiguities in measurement of coin diameters; that is, ambiguities inherent with measurement techniques that, if forced to contend with significantly variable velocities for different coins, could not effectively descriminate between a relatively large coin moving fast compared with a small coin moving slowly.
A further object is to make the system reasonably tolerant of vibrational or frictional effects.
Yet another object is to make the system, to a large degree, immune to various undesirable conditions, such as vibration and acceleration; moreover, to make the system capable of accurate diameter measurement regardless of the particular velocity initially or susequently assumed by the object, such as a coin, and regardless of significant variations between the velocities of different coins.
Still a further object is to enable extremely fast and accurate measurements to be made of the diameters of the objects passing through the system.